SB PROP @ ARL $ARLP046 ARLP046 Propagation de K7RA ZCZC AP46 QST de W1AW Propagation Forecast Bulletin 46 ARLP046 From Tad Cook, K7RA Seattle, WA November 18, 2022 To all radio amateurs SB PROP ARL ARLP046 ARLP046 Propagation de K7RA At 0334 UTC on November 18, the Australian Space Weather Forecast Centre issued this geomagnetic disturbance warning: "A moderately large coronal hole will rotate into a geoeffective location by 19-Nov. Combined with possible weak glancing interaction of recent CMEs, geomagnetic activity is expected in the coming days. "INCREASED GEOMAGNETIC ACTIVITY EXPECTED DUE TO CORONAL HOLE HIGH SPEED WIND STREAM FROM 19-20 NOVEMBER 2022." Sunspot numbers and solar flux did not seem to correlate this week. Flux rose, while spots fell. Average daily sunspot number declined from 79.8 to 72.3, but average solar flux rose from 129.9 to 137.2. This suggests the number and area of sunspots was less, but the 10.7 cm radiation from those spots increased. A new sunspot emerged on November 10, another on November 13, and two more on November 16, the last day of our reporting week, which runs Thursday through the following Wednesday. Another sunspot group emerged the next day on November 17. How is this sunspot cycle progressing? One year ago, in our bulletin average daily sunspot number was only 36.4, solar flux was 89.1, so if the latest activity seems a bit lackluster, we can see the cycle making steady progress. Solar Cycle 25 is expected to peak around July 2025, about 32 months from now. So why do we care about these numbers? We get better HF propagation at higher frequencies when x-rays from the Sun are more intense, and they correlate with sunspot numbers and the 10.7 cm radiation. This radiation charges the ionosphere, increasing density. Back in 1957-59 at the peak of Solar Cycle 19 the radiation was so intense that (I've been told) 10 meters was open worldwide, around the clock. Solar Cycle 19 had by far the highest sunspot count in recorded history, with nothing like it before or since. Here is the prediction for solar flux, from Thursday which has lower short term numbers than the Wednesday forecast presented in the ARRL Letter. Expect 118 on November 18-21, 120, 122 and 122 November 22-24, 115 on November 25-26, then 120 and 125 on November 27-28, 130 on November 29-30, 135 on December 1-12, 120 and 110 on December 13-14, then 105 on December 15-18, 110 on December 19, and 115 on December 20-23, then back to 135 before the New Year. Predicted planetary A index, which gives us a clue to possible geomagnetic unrest, is 10, 18, 28, 12 and 8 on November 18-22, 5 on November 23-24, then 15, 18, 12 and 8 on November 25-28, 5 on November 29-30, then 12, 18 and 8 on December 1-3, 5 on December 4-7, 8 on December 8-9, 5 on December 10-11, 10 on December 12-13, 5 on December 14-16, 15 on December 17, then 18 on December 18-19, and 5, 8, 15, 18, 12 and 8 on December 20-25. Coming up is the annual ARRL 10 Meter Contest, over the weekend of December 10-11. Expect better propagation than we saw in 2020 and 2021. Although predicted solar flux is not particularly high, the prediction above shows the highest solar flux (135) over that weekend, and planetary A index at a low value of 5, indicating predicted geomagnetic stability. But of course, things may change. The comment above about Solar Cycle 19 in the ARRL Letter brought this response, from a ham who was there, and just in time for Friday's bulletin. Roger, K6LMN in Los Angeles, California wrote: "10 meters SSB and the beacons most days are very good. South America comes as if over a coax cable terminating here in Los Angeles. But I need 6 more countries worked/confirmed on 10M SSB to make 150. "Also please wake up the 'magic band' 6m because I need a few more grids on 6M SSB to make 425 confirmed. "Solar Cycle 24 was OK on 6M and I'm hoping 6M goes wide open this Solar Cycle 25, after all I am 84 years old and probably this is my last solar cycle. "I need more Euro stations and am sorely lacking on the Middle East and parts of Africa. I cannot compete with you East Coasters. Namibia was coming in the other day, but the Midwest and east coasters fought it out. No luck so I gave up. Ah, but I get even with you easterners since the Pacific area is a piece of cake here in Los Angeles. "About Solar Cycle 19. I was a teenager when licensed in 1955 as a Novice. I heard stations from all over the world on HF and 6M. I hurried up and got my Tech license and then my General a few years later. "HF and 6M stations were coming in 24/7 from all over the world. I only had 90 watts and a dipole, all on AM, but WOW the stuff I worked and heard was just incredible. Mostly peaking around 1956-1957!" OK1HH writes: "Over the past two weeks, several active regions crossed the solar disk, the most significant was the trio of AR3140, AR3141 and AR3145, which crossed the central meridian on November 10-11. "Most attention was drawn to the magnetically complex and almost daily flare-producing AR3141, which allowed a smaller version of itself to grow in its northwestern part. The result (see https://bit.ly/3Askfyi ) reminded fans of 'Hitchhiker's Guide to the Galaxy President Zaphod Beeblebrox.' "The solar flux has not dropped below 130 sfu since November 5, while the Earth's magnetic field has been quiet since November 9. The result has been a relatively long period of above-average shortwave propagation conditions. "Beginning November 17, we expected an increase in geomagnetic activity as a consequence of, among other things, the CME of November 14. However, there will likely be a delay of a day or two from the original forecast. Therefore, if the disturbance begins on November 18 or 19, preferably during the daylight hours, there may be further improvement in conditions, and deterioration in the next phase of the disturbance." ARRL SSB Sweepstakes is this weekend. Even if you are not a serious contest operator, it is easy and fun to give out fresh contacts to stations on the air, especially toward the end of the event when participants are eager for new, fresh stations. A new report from Dr. Tamitha Skov, WX6SWW: https://youtu.be/xLkS3-xp5jM Here is a video that makes it appear there is a Sun serpent: https://bit.ly/3hVOLKR Thanks to reader David Moore for the following online stories on solar activity: https://bit.ly/3V6jinh https://bit.ly/3V0isIY Send your tips, reports, observations, questions, and comments to k7ra@arrl.net. For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation and the ARRL Technical Information Service at http://arrl.org/propagation-of-rf-signals . For an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere . An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation . More good information and tutorials on propagation are at http://k9la.us/ . Instructions for starting or ending email distribution of ARRL bulletins are at http://arrl.org/bulletins . Sunspot numbers for November 10 through 16, 2022 were 79, 57, 65, 74, 77, 69, and 85, with a mean of 72.3. 10.7 cm flux was 138.7, 137.6, 138.2, 137, 141.5, 134.2, and 132.9, with a mean of 137.2. Estimated planetary A indices were 2, 9, 5, 7, 4, 2, and 2, with a mean of 4.4. Middle latitude A index was 2, 9, 3, 6, 3, 2, and 2, with a mean of 3.9. NNNN /EX